JP2012228887A - Die set - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformize a contact state between a thermoplastic plate and a stamper in hot press molding.SOLUTION: A hot press molding apparatus 100 includes: a press device including a bolster 102, a slide 104, and a driving device 106 for driving the slide 104; and die sets 112 and 114. The die sets 112 and 114 include: a frame 120 having an accommodation space inside; a thermal plate 136 inserted into the frame 120 and sliding so as to change a volume of the accommodation space; a rubber member 138 accommodated in the accommodation space and compressed when the bottom plate is slid so that the accommodation space is reduced; and a flexible top panel 140 attached to the frame and having an inner surface facing the accommodation space and an outer surface supporting a stamper 142. When the thermal plate 136 slides so that the accommodation space is reduced, the top plate 140 is deformed outward by receiving an elastic force of the compressed rubber member 138 on the inner surface.

Description

  The present invention relates to a hot press molding apparatus for transferring a fine pattern onto the surface of a thermoplastic plate by pressing a stamper, and a mold system for the apparatus.

  This type of hot press molding equipment is used for optical parts and high-design panels having fine shape patterns on the surface, such as light guide plates and diffusion plates for backlights of liquid crystal displays, lenses and optical disk substrates, for example. Used for molding. A structure of a mold for this type of hot press molding is disclosed in Patent Document 1, for example. According to this disclosure, a plate-like stamper is mounted on a heating / cooling plate having heating / cooling means, the stamper is heated / cooled by the heating / cooling plate, and the stamper is made of the thermoplastic resin plate via the heating / cooling plate. Pressed against the surface.

JP 2004-74769 A

  The height of the unevenness of the shape pattern transferred by this type of hot press molding is typically several μm to several tens of μm. On the other hand, the thickness of the thermoplastic resin plate, which is a workpiece, has a variation of about ± 0.1 mm. Furthermore, there is a variation of about 0.01 to 0.05 mm in the dimensions of the mold for mounting the stamper, the thickness and flatness of the stamper itself.

  Further, in the hot press molding disclosed in Patent Document 1, the stamper is pressed against the surface of the workpiece while being heated by the heating / cooling plate, and after the stamper is cooled by the heating / cooling plate, the stamper is applied to the workpiece. End pressing. Therefore, the heating / cooling plate is warped due to thermal strain during heating / cooling.

  Due to these events, the pressure distribution on the contact surface between the stamper and the workpiece becomes non-uniform at the time of molding, and a part of the stamper cannot be pressed against the workpiece with the required pressure. As a result, a defect (untransferred) in which the pattern is not completely transferred partially occurs on the surface of the workpiece.

  In addition, when the work piece is a thin sheet material (for example, 1 mm or less), if there is a difference in the pressure distribution on the contact surface between the stamper and the work piece, the deformation of the work piece in the thickness direction A difference may occur in the amount, and a partial difference may also occur in the amount of elongation deformation in the surface direction of the workpiece. As a result, the workpiece is likely to warp or swell.

  Several measures can be considered to solve these problems. For example, a large pressing force greater than that required for transfer is applied. Alternatively, the heating temperature of the stamper is raised to lower the surface pressure necessary for transfer. Alternatively, the pressing time of the heated stamper to the workpiece is lengthened, the softened layer of the workpiece is enlarged, and the surface pressure required for transfer is lowered.

  However, these measures are not only desirable in terms of equipment cost, running cost, and production time, but also load the workpiece with a temperature or surface pressure that is higher than necessary, so that the swelling of the material side surface during molding increases. It is necessary to perform post-processing on the side of the expanded material after completion of molding. In particular, when the workpiece is a thin plate material, its warpage and undulation are increased.

  Accordingly, an object of the present invention is to make the contact state between the thermoplastic plate and the stamper uniform in hot press molding in which a concavo-convex pattern is transferred onto the surface of the thermoplastic plate.

  According to one embodiment of the present invention, a hot press molding apparatus (100) for transferring a shape pattern onto a surface of a thermoplastic plate (200) by pressing a stamper (142) includes a bolster (102), a slide ( 104) and a press device having a drive device (106) for driving the slide, and a die set (112, 114) mounted on the slide or bolster, and a frame having an accommodating space for an elastic body therein A body (120), a bottom plate (136, 326) that is inserted into the frame and slides relative to the frame so as to vary the volume of the housing space, and is housed in the housing space, the housing An elastic body (138, 328) that is compressed when the bottom plate slides so as to reduce the volume of the space, an inner surface that is attached to the frame and faces the housing space, and the A die set (112, 114) having a flexible top plate (140) having an outer surface supporting the tamper, and heating / cooling means (136, 330) for heating and cooling the stamper using a heat transfer fluid. With. When the bottom plate slides so as to reduce the volume of the accommodation space, the flexible top plate receives the elastic force of the compressed elastic body on the inner surface and deforms outward.

  In a preferred embodiment, the elastic body is a rubber member or a resin member, and the rubber member or the resin member may be filled in the accommodation space without a gap. Furthermore, the rubber member or the resin member has a first region that is in the vicinity of a region in contact with the inner surface of the frame body, and a second region inside the first region, and is filled in the first region. The first rubber member or the first resin member may have a higher hardness than the second rubber member or the second resin member filled in the second region.

  In a preferred embodiment, the heating and cooling means may be formed in the bottom plate, and the heat transfer fluid may pass through the inside of the bottom plate.

  In this case, the elastic body may be a rubber member or a resin member, and the rubber member or the resin member may be filled in the accommodation space without a gap. Furthermore, the rubber member or the resin member has a first region that is in the vicinity of a region in contact with the inner surface of the frame, and a second region inside the first region, and the second region has a thermal conductivity. It is composed of a rubber material or a resin material in which an additive for increasing the content is mixed, and the first region is not mixed with the additive, or a smaller amount of the additive is mixed in than the second region. It may be made of a rubber material or a resin material.

  In a preferred embodiment, the heating and cooling means may be a heat exchange pipe that passes through the inside of the elastic body, and the heat transfer fluid may pass through the inside of the heat exchange pipe.

  In this case, the elastic body may be a rubber member or a resin member, and the rubber member or the resin member may be filled in the accommodation space without a gap. Further, the rubber member or the resin member includes a first region formed in the vicinity of a region in contact with the inner surface of the frame body and a region in contact with the bottom plate, a region surrounded by the first region, and an inner surface of the top plate. A first rubber member or a first resin member filled in the first region is a second rubber member or a second resin member filled in the second region. The hardness may be higher.

  Alternatively, the elastic body may be a rubber member or a resin member, and the rubber member or the resin member may be filled in the accommodation space without a gap. Further, the rubber member or the resin member includes a first region formed in the vicinity of a region in contact with the inner surface of the frame body and a region in contact with the bottom plate, a region surrounded by the first region, and an inner surface of the top plate. A second region in the vicinity of a region in contact with the second region, wherein the second region is made of a rubber material or a resin material mixed with an additive for increasing thermal conductivity, and the first region is the additive Or a rubber material or a resin material in which a smaller amount of the additive is mixed than in the second region.

  In a preferred embodiment, the stamper has all outer edges of the top plate so that the top plate is outside an elastic deformation region where the top plate receives the elastic force of the elastic body on the inner surface and deforms outward. Supported by an outer surface, the hot press molding apparatus may transfer the shape pattern to the surface of the thermoplastic plate arranged so that all outer edges thereof are outside the elastic deformation region. Good.

  In a preferred embodiment, the stamper has all outer edges of the top plate so that the top plate is outside an elastic deformation region where the top plate receives the elastic force of the elastic body on the inner surface and deforms outward. The hot press molding apparatus is supported by an outer surface and has a substantially same thickness as the thermoplastic plate and is a rigid spacer, and all the outer edges of the thermoplastic plate are When inside the elastic deformation region, all the outer edges of the spacer are outside the outer edge of the elastic deformation region, and the inner edge of the spacer is slightly outside the outer edge of the thermoplastic plate. The spacer may be further provided.

  According to one embodiment of the present invention, a hot press molding apparatus (100) for transferring a shape pattern onto a surface of a thermoplastic plate (200) by pressing a stamper (142) includes a bolster (102), a slide ( 104) and a driving device (106) for driving the slide is a die set (112, 114) mounted on the slide or bolster, and a frame (120) having a space inside. And a bottom plate (136, 326) which is inserted into the frame and slides so as to change the volume of the space, and a melting point lower than a softening temperature of the thermoplastic plate housed in the space A low melting point alloy member, a top plate (140) attached to the frame and having an inner surface facing the housing space and an outer surface supporting the stamper, and using a heat transfer fluid It provided with heating and cooling means for heating and cooling the tamper (136,330), and the die sets (112, 114) having, a. When the volume of the housing space is reduced by the bottom plate, the flexible top plate receives the pressing force from the low melting point alloy member on the inner surface and deforms outward.

  In accordance with one embodiment of the present invention, a mold system for a hot press molding apparatus for transferring a concavo-convex pattern onto a surface of a thermoplastic plate by pressing a stamper is mounted on a slide or bolster of the press apparatus. A die set (112, 114) is provided, and the die set is inserted into the frame body (120) having an accommodation space for an elastic body therein, and the volume of the accommodation space is variable. A bottom plate (136, 326) that slides relative to the frame, and an elastic body (138, 328) that is accommodated in the accommodation space and is compressed when the bottom plate is slid so as to reduce the volume of the accommodation space; A flexible top plate (140) attached to the frame and having an inner surface facing the housing space and an outer surface supporting the stamper, and heating the stamper using a heat transfer fluid It provided with heating and cooling means for finely cooled (136,330), the. When the bottom plate slides so as to reduce the volume of the accommodation space, the flexible top plate receives the elastic force of the compressed elastic body on the inner surface and deforms outward.

1 shows an overall configuration of a hot press molding apparatus according to a first embodiment of the present invention. It is an enlarged view of two die sets concerning a 1st embodiment. It is explanatory drawing of the pressurization state when stamping a workpiece. It is explanatory drawing of the pressurization state when stamping a workpiece. It is explanatory drawing of the leakage prevention structure of a rubber member. The whole structure of the hot press molding apparatus concerning the 2nd Embodiment of this invention is shown. It is explanatory drawing of the leakage prevention structure of a rubber member. It is explanatory drawing of a molding motion. It is an example of the measurement result of the molding surface pressure distribution of a workpiece.

  Hereinafter, a hot press molding apparatus according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 shows an overall configuration of a hot press molding apparatus according to a first embodiment of the present invention.

  The hot press molding apparatus 100 is configured as a combination of a general-purpose press apparatus and a mold system for hot press molding. A general-purpose press device includes a bolster 102 fixed to a floor and a slide 104 disposed above the bolster 102. When the slide 104 is driven by the driving device 106, the slide 104 moves in the vertical direction along a post (not shown) so as to approach and separate from the bolster 102. The driving device 106 may include, for example, a servo motor that drives the slide 104 and a controller that drives and controls the servo motor. As the driving device 106, a device using a hydraulic actuator may be used instead of a device using a servo motor.

  The mold system includes two upper and lower die sets 112 and 114 mounted on the bolster 102 and the slide 104 so as to face each other. FIG. 2 is an enlarged view of these two die sets 112 and 114 according to the first embodiment. Since the two die sets 112 and 114 have substantially the same configuration, the configuration of the upper die set 112 will be described as an example with reference to FIGS. 1 and 2.

  The upper die set 112 includes a base plate 116, a cooling plate 118, a frame body 120, a frame body support mechanism 122, a heat plate 136, a rubber member 138 as an elastic body, a flexible top plate 140, a frame 126.

  The base plate 116 has a substantially rectangular plate shape and is fixed on the slide 104.

  The cooling plate 118 has a substantially rectangular plate shape and is fixed to the center of the base plate 116. A plurality of water holes 119 are formed in the cooling plate 118, and each water hole 119 is connected. Cooling water is supplied to the cooling water supply port connected to one end of the connected water hole 119, and the cooling water is circulated from the cooling water return port connected to the other end of the connected water hole. Thus, the temperature of the cooling plate 118 is kept constant, and the heat of the hot plate is blocked from being transmitted to the base plate 116 side.

  The frame support mechanism 122 is fixed on the cooling plate 118. The frame body support mechanism 122 and the frame body 120 are substantially rectangular cylinders. The frame body support mechanism 122 includes a base block 128 and a spring 130, and the base block 128 supports the frame body 120 via the spring 130. The frame body 120 is urged downward by a spring 130. The bottom of the frame body support mechanism 122 is open, and the hot plate 136 is inserted into the frame body support mechanism 122 and the frame body 120 from the opening.

  The frame 126 has a substantially rectangular ring shape and is fixed on the base plate 116. On the head surface of the frame 126, an annular sealing frame 132 having a vacuum packing is attached. When the frame 126 descends and the sealing frame 132 contacts the sealing frame 132 of the lower die set 114, a vacuum chamber is formed inside the sealing frame. The vacuum chamber is freely evacuated by a vacuum pump (not shown) and released to the atmosphere by an atmosphere release valve.

  The hot plate 136 has a substantially rectangular plate shape and is fixed on the cooling plate 118. The hot plate 136 is a heating / cooling means, and a plurality of water holes 141 serving as passages for the heat transfer fluid are formed therein. The water holes 141 are formed, for example, at equal pitches parallel to each other along the longitudinal direction of the hot plate, penetrating from one end surface to the other end surface of the hot plate 136, and both ends are sealed with stoppers 143. It is. Each water hole 141 is connected by a manifold 145 provided on both sides in the longitudinal direction of each water hole 141. At the time of heating, a high-temperature heat medium fluid (steam, high-temperature oil, etc.) supplied from a heat medium supply port connected to one manifold 145 passes through each water hole 141 and is discharged from the other manifold 145. Thereby, the rubber member 138 is heated. At the time of cooling, a low-temperature heat transfer fluid (cooling water, low-temperature oil, etc.) passes through each water hole 141 through the same path, and the rubber member 138 is cooled. A heat insulating slit 147 is formed inside the manifold 145 of the hot plate 136 to prevent heat diffusion of the manifold 145.

  The hot plate 136 is inserted into the frame 120, and the inner surface of the frame 120 and the outer surface of the hot plate 136 are in close contact with each other. With the inner surface of the frame 120 and the outer surface of the hot plate 136 in close contact with each other, the hot plate 136 can move in the vertical direction (the thickness direction of the workpiece) with respect to the frame 120. In other words, the frame body 120 is movable in the vertical direction with respect to the heat plate 136. That is, the hot plate 136 serves as a bottom plate by sliding with respect to the frame body 120.

  A flexible top plate 140 is fixed to the head surface of the frame body 120 by a fixing means such as a bolt. The top plate 140 is fixed so as to seal the opening 121 on the head surface of the frame body 120. The thickness of the top plate 140 may be about 0.5 to 3 mm, for example.

  The frame 120 forms an accommodation space 124 by the top plate 140, the heat plate 136, and the side wall of the frame 120. A rubber member 138 is accommodated in the accommodation space 124. The housing space 124 is substantially sealed so that the rubber member 138 does not leak. The volume of the enclosed storage space 124 changes as the hot plate 136 slides with respect to the frame body 120.

  The rubber member 138 is accommodated in an accommodation space 124 formed by the heat plate 136, the frame body 120, and the top plate 140. For example, the accommodation space 124 may be filled with the rubber member 138 without a gap. The rubber member 138 may have a higher thermal conductivity. The material of the rubber member 138 will be described later.

In the present specification, an embodiment using a rubber member as an example of an elastic body member will be mainly described. However, other elastic bodies such as a synthetic resin can be applied instead of rubber. As an example of the synthetic resin, a fluororesin may be used. Among fluororesins, for example, tetrafluoroethylene resin (PTFE) may be used. PTFE has the following physical properties.
Heat resistance: 260 ° C
Tensile strength: 13.7 to 34.3 MPa
Elongation: 200-400%
Hardness: Shore-D50-55
Flexural modulus: 550 GPa
Tensile modulus: 400-550 GPa
Thermal conductivity: 0.25 W / mk

  A flexible thin stamper 142 is fixed to the outer surface (head surface) of the head of the die set 112. As a method for fixing the stamper 142, for example, vacuum suction using a vacuum suction groove processed on the outer surface of the top plate 140 (illustration of a vacuum pump is omitted), and fixing treatment provided on the outer surface of the top plate 140 are performed. Combinations with tools can be used.

  FIG. 3B is an explanatory diagram of a pressurized state when stamping the workpiece 200, and FIG. 3A is a cross-sectional view taken along line AA.

  As shown in FIG. 3A, the size of the stamper 142 is larger than the opening 121 of the frame body 120, and is in close contact with the outer surface of the top plate 140 so that all outer edges thereof are outside the opening 121. The size of the workpiece 200 is also larger than the opening 121 of the frame body 120 and is set so that all the outer edges are outside the opening 121.

  Hereinafter, the operation when stamping the workpiece 200 will be described with reference to FIGS. Here, the operation of the upper and lower die sets 112 and 114 will be described, and temperature control will be described later.

  When the upper die set 112 is lowered with respect to the lower die set 114 set as shown in FIG. 1, the upper and lower stampers 142 and 142 come into contact with both surfaces of the workpiece 200 (pressurization start state). The state at this time is the left side of FIG. 3B. When the upper die set 112 is further lowered from the state in which the upper and lower stampers 142 and 142 are in contact with both surfaces of the workpiece 200 and a pressing force is applied, the frame body 120 also resists the urging force of the spring 130 to the base plate 116 side. Retreat to. At the same time, the rubber member 138 receives the pressing force from the hot plate 136 and the repulsive force from the workpiece 200 to reduce the volume and increase the internal pressure. That is, the rubber member 138 is compressed. Then, the hot plate 136 moves forward relative to the frame body 120 by the amount that the rubber member 138 has reduced its volume by compression.

  At this time, the compressed rubber member 138 generates a uniform pressing force by elasticity. Therefore, if the rubber member 138 is filled in the housing space 124 formed by the frame body 120, the hot plate 136, and the top plate 140 without any gaps, the compressed rubber member 138 causes the pressure in the housing space 124 to be increased. Ascend evenly. At this time, since the frame body 120 is pressed against the top plate 140 by the urging force of the spring 130, the rubber member 138 does not leak from the gap between the top plate 140 and the frame body 120. Here, except for the flexible top plate 140, all the walls forming the accommodation space 124 are rigid bodies and are not deformed by the elastic force of the compressed rubber member 138. On the other hand, the flexible top plate 140 is deformed so as to bulge outward by receiving the elastic force of the compressed rubber member 138 on the inner surface. Here, the elastic deformation region in which the flexible top plate 140 deforms so as to bulge outward is substantially the same as the opening 121 of the frame body 120.

  At the time of hot press molding as shown in FIG. 3B, the upper and lower stampers 142, 142 are pressed against the upper and lower surfaces of the workpiece 200, which is a thermoplastic resin plate. At this time, since all the outer edges of the workpiece 200 are outside the opening 121 of the frame body 120, all of the elastically deforming regions that are deformed so that the flexible top plate 140 bulges outward are processed. It fits inside the outer edge of the material 200. As a result, the stampers 142 and 142 are not locally deformed at the outer edge portion of the workpiece 200 as the flexible top plate 140 is deformed, and the stampers 142 and 142 are formed on the surface of the workpiece 200. The pressure distribution is more uniform than before.

  In the case of this method, with respect to the workpiece 200 in the frame region around the elastic deformation region where the flexible top plate 140 bulges outward, the flexible top plate 140 does not bulge outward. Cannot be evenly pressurized. Therefore, the pattern may not be accurately transferred to the frame body region. At that time, the workpiece 200 in the frame region may be trimmed after molding.

  In FIG. 3, the case where the size of the workpiece 200 is larger than the opening 121 of the frame 120 has been described, but FIG. 4 illustrates the case where the size of the workpiece 200 is smaller than the opening 121 of the frame 120. It is explanatory drawing. That is, FIG. 4B is an explanatory diagram of a pressurized state when stamping the workpiece 200 in which the size of the workpiece 200 is smaller than the opening 121 of the frame body 120, and FIG. FIG.

  As shown in FIG. 4A, first, the stamper 142 is in close contact with the outer surface of the top plate 140 as in FIG. 3A. Since the size of the workpiece 200 is smaller than the opening 121 of the frame, the workpiece 200 is set on the stamper 142 so that all the outer edges of the workpiece 200 are in the opening 121. In this case, a rigid spacer 210 is further fixed on the stamper 142 around the workpiece 200.

  The inner shape (inner edge) of the rigid spacer 210 is slightly larger than the outer edge of the workpiece 200. That is, there is a slight gap between the workpiece 200 and the rigid spacer 210. The outer shape (outer edge) of the rigid spacer 210 is larger than the opening 121 of the frame body 120. Further, the plate thickness of the rigid spacer 210 may be substantially the same as the thickness of the workpiece 200 or may be slightly thick. For example, the maximum thickness of the plate thickness variation of the workpiece 200 may be about +0.1 mm. The material of the rigid spacer 210 may be the same material as the top plate 140 and the stamper 142, such as stainless steel (SUS). The clearance between the rigid spacer 210 and the workpiece 200 and the plate thickness of the rigid spacer 210 are adjusted according to the thickness of the top plate 140, the stamper 142, and the workpiece 200, so that the workpiece 200 can be added. When the pressure is applied, the rigid spacer 210 is also pressurized, and the entire rubber member 138 is uniformly compressed in a sealed state. That is, as in the case of FIG. 3, local deformation of the stamper 142 can be prevented and the workpiece 200 can be evenly pressurized.

  Here, the thickness of the rubber member 138 is preferably thinner in view of the fact that the heat of the hot plate 136 is quickly transmitted to the top plate 140 and the stamper 142 attached to the top plate 140. On the other hand, when the rubber member 138 is compressed, the thicker one is desirable in view of the effect of pushing the top plate 140 with a uniform pressure. Therefore, the plate pressure of the rubber member 138 may be about 2 to 5 mm, for example.

  Further, as a material of the rubber member 138, for example, silicone rubber can be used. Since silicone rubber generally has a low thermal conductivity, the thermal conductivity is increased by adding an additive (alumina, ceramic, etc.) to the base silicone. Generally, when the amount of the additive is increased, the thermal conductivity of the silicone rubber is improved, but its hardness is lowered, and the silicone rubber is in a gel or clay state. When PTFE is used instead of the rubber material, it is not always necessary to adjust the thermal conductivity by mixing the additive as described above, but an additive may be mixed.

  When a rubber material having low hardness is used as the rubber member 138, the rubber member 138 may leak from a slight gap between the outer side surface of the hot plate 136 and the inner side surface of the frame 120 during pressurization. In order to prevent this, rubber materials having different hardnesses may be combined as the rubber member 138 as follows.

  For example, FIG. 5B is an explanatory diagram of the lower die set 114 when a rubber material of a different material is combined with the rubber member 138, and FIG. 5A is a cross-sectional view taken along the line AA.

  As shown in these drawings, a peripheral region 139A of a rubber member 138 having a substantially rectangular plate shape is made of high hardness silicone rubber (for example, Shore hardness A70 or more), and is surrounded by the high hardness silicone rubber. The region 139B may be made of high heat conductive silicone rubber having low hardness. The rubber material having a high hardness in the peripheral region 139A may have a smaller amount of additive than the rubber material having a low hardness in the inner region 139B, or may contain no additive at all. Thereby, it is possible to prevent the rubber member 138 from entering between the frame body 120 and the hot plate 136 during pressurization.

  The thermal conductivity of the rubber member 138 constituting the peripheral region 139A may be low. When the thermal conductivity of the rubber member 138 constituting the peripheral region 139A is low, thermal conduction from the hot plate 136 to the frame body 120 is inhibited, and thermal expansion and thermal contraction of the frame body 120 can be suppressed.

  Further, a configuration as shown in FIG. 5 may be realized by using a synthetic resin material instead of the rubber material. That is, the peripheral region 139A may be made of a synthetic resin material having high hardness, and the inner region 139B may be made of a synthetic resin material having low hardness.

  Furthermore, the rubber member 138 can be replaced with a combination of a rubber material and a synthetic resin material. That is, the peripheral region 139A may be made of a fluororesin and the inner region 139B may be made of a rubber material.

  Further, instead of combining rubber materials having different hardnesses as the rubber member 138 as described above, an O-ring may be provided at a location where the rubber member 138 is likely to leak during pressurization. For example, as shown in FIG. 5C, O-rings 230 may be provided on the surface of the frame 120 that contacts the top plate 140 and the outer surface of the heat plate 136 that contacts the inner surface of the frame 120. .

  In addition, as a material of the rubber member 138, you may use the fluorine rubber which is more excellent in abrasion resistance and mechanical strength than a silicone rubber.

  FIG. 6 shows the overall configuration of a hot press molding apparatus according to the second embodiment of the present invention.

  The second embodiment is different from the first embodiment mainly in heating / cooling means for the rubber member, and many other points are common. Hereinafter, the difference will be mainly described, and description of points that are common to the first embodiment may be omitted.

  Also in this embodiment, since the upper die set 312 and the lower die set 314 have substantially the same configuration, the upper die set 312 will be described as an example. The upper die set 312 includes a base plate 116, a spacer 322, a frame body 120, a spring 130, a heat insulating plate 326, a rubber member 328, a heat exchange pipe 330, a flexible top plate 140, and a frame 126. Is provided.

  The spacer 322 has a substantially rectangular plate shape and is fixed on the base plate 116. The frame body 120 is attached to the spacer 322 via a spring 130. The cooling plate 118 is fixed on the spacer 322. The heat insulating plate 326 has a substantially rectangular plate shape and is fixed on the cooling plate 118. The outer surface of the heat insulating plate 326 and the inner surface of the frame 120 are in close contact. The heat insulating plate 326 blocks heat conduction between the rubber member 328 and the cooling plate 118. As a material of the heat insulating plate 326, for example, a heat resistant epoxy resin may be used.

  In the present embodiment, similarly to the first embodiment, the accommodation space 124 is formed by the top plate 140, the heat insulating plate 326, and the side wall of the frame body 120. A rubber member 328 is accommodated in the accommodating space 124. As the rubber member 328, the same material as that of the first embodiment can be used. In the present embodiment, the heat exchange pipe 330 passes through the accommodation space 124. A space other than the heat exchange pipe 330 in the accommodation space 124 is filled with the rubber member 328 without any gap.

  The heat exchange pipes 330 are arranged at an equal pitch in parallel with each other along the longitudinal direction of the accommodation space. Both ends of the heat exchange pipe 330 pass through the frame body 120 and are connected by manifolds 342 and 342 provided outside the frame body 120. During heating, when a high-temperature heat medium fluid (steam, high-temperature oil, etc.) is supplied from the heat medium supply port connected to one manifold 342, the high-temperature heat medium fluid passes through the heat exchange pipe 330. And is discharged from the other manifold 342. Thereby, the rubber member 328 is heated. At the time of cooling, a low-temperature heat transfer fluid (cooling water, low-temperature oil, etc.) passes through the heat exchange pipe 330 through the same path, and the rubber member 328 is cooled.

  The heat insulating plate 326 can move in the vertical direction (the thickness direction of the workpiece) with respect to the frame 120 in a state where the inner surface of the frame 120 and the outer surface of the heat insulating plate 326 are in close contact with each other. The volume of the accommodation space 124 changes due to the same as in the first embodiment. Further, in the present embodiment, similarly to the first embodiment, the workpiece 200 having a size larger than the opening 121 of the frame body 120 can be stamped. A workpiece 200 having a size smaller than the opening 121 of the body 120 can be stamped.

  Next, the material and configuration of the rubber member 328 in the second embodiment will be described.

  For example, FIG. 7A is an explanatory diagram of the lower die set 314 when different rubber materials are combined with the rubber member 328.

  As shown in the figure, in the rubber member 328 having a substantially rectangular plate shape, a region 329A in the vicinity of the surface in contact with the frame 120 and the heat insulating plate 326 is composed of high hardness silicone rubber, and the other region, that is, rubber The central region of the member 328 and the region 329 </ b> B in the vicinity of the surface in contact with the inner surface of the top plate 140 may be made of high heat conductive silicone rubber with low hardness. That is, in the housing space formed by the top plate 140, the frame body 120, and the heat insulating plate 326, the high hardness silicone rubber is disposed between the low heat hardness silicone rubber and the frame body 120 and the heat insulating plate 326. It may be. The rubber material having a high hardness in the region 329A may have a smaller amount of additive than the rubber material having a low hardness in the region 329B, or may contain no additive at all. Thereby, it is possible to prevent the rubber member 328 from entering between the frame body 120 and the heat insulating plate 326 during pressurization.

  The rubber member 328 constituting the region 329A in the vicinity of the surface in contact with the frame body 120 and the heat insulating plate 326 may have a low thermal conductivity. In that case, heat conduction from the heat exchange pipe 330 to the frame body 120 is hindered, and thermal expansion and contraction of the frame body 120 can be suppressed.

  As in the case of the first embodiment, a configuration as shown in FIG. 7 may be realized by using a synthetic resin material instead of the rubber material. In other words, the region 329A in the vicinity of the surface in contact with the frame 120 and the heat insulating plate 326 is a synthetic resin material having high hardness, and the region 329B in the vicinity of the surface in contact with the center region of the rubber member 328 and the inner surface of the top plate 140 is combined with low hardness. You may comprise with a resin material.

  Furthermore, the rubber member 328 can be replaced with a combination of a rubber material and a synthetic resin material. That is, the peripheral region 329A may be made of fluororesin, and the region 329B in the vicinity of the surface in contact with the center region and the inner surface of the top plate 140 may be made of a rubber material.

  Moreover, as shown to FIG. 7B, an O-ring can also be provided. That is, as shown in the figure, an O-ring may be provided at a location where the rubber member 328 is likely to leak during pressurization. For example, O-rings 230 may be provided on the surface of the frame body 120 that contacts the inner surface of the top plate 140 and the outer surface of the heat insulating plate 326 that contacts the inner surface of the frame body 120.

  According to this embodiment, since a complicated hot plate is not required, the die set can be easily enlarged.

  Next, with reference to FIG. 8, the molding motion in the hot press molding apparatus 100 according to the first and second embodiments of the present invention will be described. 8A shows the slide position, FIG. 8B shows the pressing force, FIG. 8C shows the top plate temperature, and FIG. 8D shows the respective changes in one cycle of the molding motion in the vacuum chamber pressure.

  First, the slide 104 is at the upper limit position S1. The workpiece 200 is set on the stamper 142 of the lower die set 114 until time t1.

  At time t1, the slide 104 starts to descend according to the position control of the servo press. Then, when the sealing frames 132 on the head surfaces of the frames 126, 126 of the upper and lower die sets 112, 114 come into contact with each other and descend to the position S2 where the vacuum chamber is formed, the descending of the slide 104 is temporarily stopped (time t2). ).

  At time t2, evacuation in the vacuum chamber is started, and supply of a high-temperature heat transfer fluid to the hot plate 136 (heat exchange pipe 330 in the second embodiment) is started. The stampers 142 and 142 are not pressurized against the workpiece 200 until the time t3 when the vacuuming is performed. This is to prevent air from entering between the workpiece 200 and the stampers 142, 142.

  At time t3 when the degree of vacuum in the vacuum chamber reaches the degree of vacuum P2 suitable for transfer molding from the atmospheric pressure P1, the slide 104 starts to descend again according to the pressurization control of the servo press. The degree of vacuum P2 may be −90 KPa or less, for example. Then, the upper and lower stampers 142 and 142 are pressed against the workpiece 200 with the preliminary pressurizing force L1. By pressing the upper and lower stampers 142, 142 against the workpiece 200 with the preliminary pressure L1, the hot plate 136 (heat exchange pipe 330 in the second embodiment), the rubber member 138, the top plate 140, and the stamper 142 are in close contact with each other. Heat conduction from the hot plate 136 (heat exchange pipe 330 in the second embodiment) is promoted. For example, the surface pressure applied to the pressing surface of the workpiece 200 may be about 1 MPa.

  At time t4 when the temperature of the top plate 140 reaches the transferable temperature H2, the slide 104 is further lowered to be controlled to a transfer pressure L2 at which the stamper can be transferred. The transfer pressure L2 is set such that the surface pressure applied to the pressure surface of the workpiece 200 is 4 to 6 MPa, for example. If the workpiece 200 is a PMMA material, the transferable temperature H2 may be 120 to 150 ° C., for example.

  Then, pressurization in the heated state is continued for a predetermined time T from time t5 when the applied pressure reaches the transfer applied pressure L2. At time t6 when the predetermined time T has elapsed, supply of a low-temperature heat transfer fluid to the heat plate 136 (heat exchange pipe 330 in the second embodiment) is started, and cooling of the top plate 140 and the stamper 142 is started. The predetermined time T is optimally set according to the material of the workpiece and the shape of the stamper so as not to cause a transfer failure such as untransferred.

  At time t7 when the top plate 140 and the stamper 142 are cooled and the temperature reaches the mold releaseable temperature H1, the vacuum chamber is opened to the atmosphere, and the pressure in the vacuum chamber returns to the atmospheric pressure P1. When the workpiece is a PMMA material, the mold release possible temperature H1 may be 40 to 70 ° C., for example.

  At the time t8 when the pressure in the vacuum chamber returns to the atmospheric pressure P1, the slide 104 starts to rise again according to the position control. Then, the slide 104 returns to the upper limit position S1, and the workpiece 200 can be taken out.

  An example of the molding surface pressure distribution when the workpiece is pressed by the hot press molding apparatus according to the embodiment described above is shown in FIG. This figure shows the distribution of the molding surface pressure when an acrylic workpiece (256 mm × 159 mm, thickness 0.2 mm) smaller than the opening 121 of the frame body 120 is pressed with a load equivalent to 6 MPa. Fig. A shows the distribution of molding surface pressure in a conventional die set that does not use a rubber member. Fig. B shows the mode shown in Fig. 4 in the first embodiment (using a rigid spacer, the rubber member is thick). This is the distribution of the molding surface pressure of 2 mm thick silicone rubber). In the figure, a darker color portion indicates a higher pressure, and a lighter color portion indicates a lower pressure.

  As shown in FIG. 9A, the molding surface pressure of the workpiece portion 250 has a large unevenness. That is, the molding surface pressure in the vicinity of the outer edge of the workpiece portion 250 is high, and the molding surface pressure in the other region of the workpiece portion 250 is lower than that in the vicinity of the outer edge.

  On the other hand, as shown in FIG. 9B, a rigid spacer portion 260 exists around the workpiece portion 250. And according to this embodiment, it turns out that distribution of the molding surface pressure of the workpiece part 250 is substantially equal.

  In any of the above embodiments, a low melting point alloy having a melting point lower than the softening temperature of the thermoplastic workpiece may be used instead of the rubber member. Low melting point alloy is a property that lowers the melting point by alloying with different types of metals (Pb (lead), Bi (bismuth), Sn (tin), Cd (cadmium), In (indium), etc.) It means a known alloy using

  According to the two embodiments described above, the stamper can be pressed against the surface of the workpiece with a uniform pressure. As a result, since the workpiece can be compressed with a uniform pressure, it is possible to reduce non-uniformity of internal strain generated inside the workpiece, and to reduce waviness and warpage of the workpiece.

  In addition, by compressing the rubber member in a sealed state, the elastic body exhibits characteristics close to that of an incompressible fluid, and the pressure surface pressure can be equalized by the hydrostatic pressure effect. The pressure variation due to the variation in hardness and elastic modulus is also reduced.

  Furthermore, since only compressive stress is generated inside the rubber member, the elastic body is prevented from tearing due to tensile stress. In addition, since no slip occurs between the rubber member and the hot plate and between the rubber member and the top plate, wear of the rubber member is also prevented.

  The above-described embodiments of the present invention are examples for explaining the present invention, and are not intended to limit the scope of the present invention only to those embodiments. Those skilled in the art can implement the present invention in various other modes without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 100 ... Hot press molding apparatus, 102 ... Bolster, 104 ... Slide, 106 ... Drive apparatus, 112, 114, 312, 314 ... Die set, 118 ... Cooling plate, 120 ... Frame, 124 ... Storage space, 136 ... Hot plate DESCRIPTION OF SYMBOLS 138,328 ... Rubber member, 140 ... Top plate, 142 ... Stamper, 200 ... Work material, 210 ... Rigid spacer, 322 ... Spacer, 330 ... Heat exchange pipe.

Claims (11)

A pressing device having a bolster (102), a slide (104), and a driving device (106) for driving the slide is mounted on the slide or bolster, and a stamper (142) is pressed against a thermoplastic plate (200). A die set (112, 114) for transferring the shape pattern to the surface of
A frame (120) having an accommodating space for an elastic body therein;
A bottom plate (136, 326) that is inserted into the frame and slides relative to the frame so as to vary the volume of the accommodation space;
An elastic body (138, 328) that is filled in the accommodation space without a gap and is compressed when the bottom plate slides so as to reduce the volume of the accommodation space;
A flat plate attached to the frame, having an inner surface facing the housing space and an outer surface supporting the stamper, and when the bottom plate slides so as to reduce the volume of the housing space, the elasticity of the elastic body A flexible top plate (140) that receives force on the inner surface and deforms outward;
And a heating / cooling means (136, 330) for heating and cooling the stamper using a heat transfer fluid. A base plate (116) interposed between the slide or bolster and the bottom plate;
The die set according to claim 1, further comprising a spring (130) interposed between the base plate and the frame body and biasing the frame body outward. The elastic body is a rubber member or a resin member,
The rubber member or the resin member has a first region in the vicinity of a region in contact with the inner surface of the frame body, and a second region inside the first region, and the first region is filled in the first region. The die set according to claim 1 or 2, wherein the rubber member or the first resin member has a higher hardness than the second rubber member or the second resin member filled in the second region.   The die set according to claim 1 or 2, wherein the heating / cooling means is formed in the bottom plate, and the heat transfer fluid passes through the inside of the bottom plate. The elastic body is a rubber member or a resin member,
The rubber member or the resin member has a first region in the vicinity of a region in contact with the inner surface of the frame body, and a second region inside the first region, and the second region increases the thermal conductivity. The first region is not mixed with the additive, or a smaller amount of the additive is mixed with the second region than the second region. The die set according to claim 4, wherein the die set is made of a rubber material or a resin material.   The die set according to claim 1 or 2, wherein the heating / cooling means is a heat exchange pipe that passes through the inside of the elastic body, and the heat transfer fluid passes through the inside of the heat exchange pipe. The elastic body is a rubber member or a resin member,
The rubber member or the resin member is in contact with a first region including a region in contact with the inner surface of the frame and a region in contact with the bottom plate, a region surrounded by the first region, and an inner surface of the top plate. The first rubber member or the first resin member filled in the first region is harder than the second rubber member or the second resin member filled in the second region. The die set according to claim 6, wherein the die set is high. The elastic body is a rubber member or a resin member,
The rubber member or the resin member is in contact with a first region including a region in contact with the inner surface of the frame and a region in contact with the bottom plate, a region surrounded by the first region, and an inner surface of the top plate. A second region in the vicinity of the region, and the second region is made of a rubber material or a resin material mixed with an additive for increasing thermal conductivity, and the first region is mixed with the additive. The die set according to claim 6, wherein the die set is made of a rubber material or a resin material that is not formed or is mixed with a smaller amount of the additive than the second region. The stamper is supported on the outer surface of the top plate so that all outer edges thereof are outside an elastic deformation region in which the top plate receives the elastic force of the elastic body and deforms outward. ,
The die set is
The die set according to any one of claims 1 to 8, wherein a shape pattern is transferred onto the surface of the thermoplastic plate arranged so that all outer edges thereof are outside the elastic deformation region. . The stamper is supported on the outer surface of the top plate so that all outer edges thereof are outside an elastic deformation region in which the top plate receives the elastic force of the elastic body and deforms outward. ,
The die set is
A spacer made of a rigid body having substantially the same thickness as the thermoplastic plate, wherein all the outer edges of the thermoplastic plate are inside the elastic deformation region. It further comprises a spacer fixed so that all outer edges are outside the outer edge of the elastic deformation region and the inner edge of the spacer is slightly outside the outer edge of the thermoplastic plate. The die set according to any one of claims 1 to 8. A pressing device having a bolster (102), a slide (104), and a driving device (106) for driving the slide is mounted on the slide or bolster, and a stamper (142) is pressed against a thermoplastic plate (200). A die set (112, 114) for transferring the shape pattern to the surface of
A frame (120) having a space inside;
A bottom plate (136, 326) that is inserted into the frame and slides to vary the volume of the space;
A low melting point alloy member having a melting point lower than the softening temperature of the thermoplastic plate, which is filled in the space without a gap;
A flat plate attached to the frame, having an inner surface facing the space and an outer surface supporting the stamper, and when the bottom plate slides so as to reduce the volume of the space, from the low melting point alloy member A flexible top plate (140) that receives a pressing force on its inner surface and deforms outward;
And a heating / cooling means (136, 330) for heating and cooling the stamper using a heat transfer fluid.

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